Authentication structure and authentication method using the same

Abstract

An authentication structure and an authenticating method using the same are provided. The authentication structure includes a plurality of input couplers that generate surface plasmons by being selectively coupled to lights because the plurality of input couplers are different in terms of at least one of a geometric structure and an arrangement, and an output coupler that outputs a speckle pattern based on the surface plasmons.

What is claimed is: 
     
       1. An authentication structure comprising:
 a first input coupler oriented in a first direction and configured to generate first surface plasmons from first light having first light characteristics from among incident light; 
 a second input coupler oriented in a second direction different from the first direction and configured to generate second surface plasmons from second light having second light characteristics from among the incident light; and 
 an output coupler spaced apart from the first and second input couplers, the output coupler comprising a plurality of optical scatterers, each of which reacting differently according to characteristics of the first and second surface plasmons due to at least one of locations, sizes, and an arrangement of the plurality of optical scatterers, and configured to output different speckle patterns based on the characteristics of the first and second surface plasmons and the plurality of the optical scatterers. 
 
     
     
       2. The authentication structure of  claim 1 , wherein a polarization of the first light is different from a polarization of the second light, a wavelength of the first light is different from a wavelength of the second light, or the polarization and the wavelength of the first light are different from the polarization and the wavelength of the second light. 
     
     
       3. The authentication structure of  claim 1 , wherein an included angle between the first direction and the second direction is less than 180°. 
     
     
       4. The authentication structure of  claim 3 , wherein the first direction and the second direction intersect at 90°. 
     
     
       5. The authentication structure of  claim 1 , wherein the first input coupler and the second input coupler are spaced apart from each other. 
     
     
       6. The authentication structure of  claim 5 , wherein the first input coupler and the second input coupler partially overlap each other. 
     
     
       7. The authentication structure of  claim 1 , wherein a length of the first input coupler is different from a length of the second input coupler. 
     
     
       8. The authentication structure of  claim 1 , wherein the first input coupler is coupled to light having a polarization characteristic that is parallel to the first direction. 
     
     
       9. The authentication structure of  claim 1 , wherein the first output coupler outputs a first speckle pattern based on the first surface plasmons, outputs a second speckle pattern based on the second surface plasmons, and outputs a third speckle pattern based on the first and second surface plasmons. 
     
     
       10. The authentication structure of  claim 1 , further comprising a waveguide configured to transmit at least one of the first and second surface plasmons to the output coupler. 
     
     
       11. The authentication structure of  claim 1 , wherein
 the authentication structure comprises a layer structure that is a single-layer structure or a multi-layer structure, 
 the first and second input couplers are provided in a first area of the layer structure, and 
 the output coupler is provided in a second area of the layer structure. 
 
     
     
       12. The authentication structure of  claim 11 , wherein the first area is at a first distal end of the layer structure and the second area is at a second distal end of the layer structure. 
     
     
       13. The authentication structure of  claim 11 , wherein the first and second input couplers comprise at least one of a slit and a slot disposed in the first area of the layer structure. 
     
     
       14. The authentication structure of  claim 11 , wherein the output coupler comprises a plurality of optical scatterers disposed in the second area of the layer structure. 
     
     
       15. The authentication structure of  claim 14 , wherein each of the plurality of optical scatterers has a nanoscale size or a microscale size. 
     
     
       16. The authentication structure of  claim 14 , wherein at least one of the plurality of optical scatterers comprises a slit, a slot, a spherical element, or a rod-type element. 
     
     
       17. The authentication structure of  claim 11 , wherein the layer structure comprises a metal film. 
     
     
       18. A method of authenticating an authentication structure including a plurality of input couplers that have different geometric structures or arrangements from each other and an output coupler, the method comprising:
 emitting light to the plurality of input couplers; and 
 generating surface plasmons by the plurality of input couplers being selectively coupled to lights having different light characteristics among the emitted light; and 
 detecting different speckle patterns output by the output coupler based on characteristics of the surface plasmons and a plurality of optical scatterers included in the output coupler, 
 wherein each of the plurality of optical scatterers reacts differently according to the characteristics of the surface plasmons due to at least one of locations, sizes, and an arrangement of the plurality of optical scatterers, and 
 wherein at least two of the plurality of input couplers are oriented in different directions from each other. 
 
     
     
       19. An authentication device comprising:
 a light source configured to emit, to a layer structure, a first laser beam having a first polarization and a second laser beam having a second polarization different from the first polarization; 
 a first input coupler disposed on the layer structure in a first direction, the first input coupler being configured to generate first surface plasmons in response to the first laser beam being incident on the first input coupler; 
 a second input coupler disposed on the layer structure in a second direction different from the first direction, the second input coupler being configured to generate second surface plasmons in response to the second laser beam being incident on the second input coupler; and 
 an output coupler disposed on the layer structure and comprising a plurality of optical scatterers, each of which reacting differently according to characteristics of the first and second surface plasmons due to at least one of locations, sizes, and an arrangement of the plurality of optical scatterers, 
 wherein the output coupler is configured to generate a first speckle pattern in response to the first surface plasmons traveling along the layer structure and reaching the output coupler, and generate a second speckle pattern different from the first speckle pattern in response to the second surface plasmons traveling along the layer structure and reaching the output coupler, based on the characteristics of the first and second surface plasmons and the plurality of the optical scatterers.